University of Western Sydney, School of Medicine, NSW, Australia.
Hypertension. 2013 Apr;61(4):880-5. doi: 10.1161/HYPERTENSIONAHA.111.00698. Epub 2013 Feb 11.
The microvasculature plays an important role in regulating cardiovascular changes in pregnancy, but changes in microvasculature have been difficult to document in vivo. This study objectively quantifies changes in the maternal retinal arteriolar and venular caliber over the course of healthy pregnancy. Healthy pregnant women (n=53) were recruited from Royal Prince Alfred Hospital, Sydney, Australia. Retinal images and mean arterial blood pressures (MAP) were collected at 13, 19, 29, and 38 weeks of gestation and at 6-month postpartum. Retinal vessels were analyzed and summarized as the central retinal arteriolar equivalent and central retinal venular equivalent. Central retinal arteriolar equivalent and central retinal venular equivalent were corrected for MAP. Paired t tests were performed comparing consecutive time points, with a significance level of P<0.01. There was a decrease in MAP between 13- and 19-week gestation (P=0.001) followed by a return to baseline from 19 weeks to delivery. This was correlated by an increase in vessel caliber between 13- and 19-week gestation (central retinal arteriolar equivalent: P<0.001, central retinal venular equivalent: P=0.007) and a return to baseline from 19 weeks to delivery. There were no differences in the central retinal arteriolar equivalent or central retinal venular equivalent (both uncorrected and corrected for MAP) between nulliparous and parous women. The pattern of dilatation and constriction in the microvasculature mirrored the changes in MAP throughout pregnancy, reflecting changes in peripheral resistance. This study provides insights into physiological changes in the microvasculature throughout a healthy pregnancy. These results can be used as a baseline with which to compare the changes observed in pathological conditions of pregnancy.
微血管在调节妊娠期间心血管变化方面起着重要作用，但微血管的变化在体内很难被记录下来。本研究客观地量化了健康妊娠过程中母体视网膜小动脉和小静脉口径的变化。研究人员从澳大利亚悉尼的皇家阿尔弗雷德王子医院招募了 53 名健康孕妇。在妊娠 13、19、29 和 38 周以及产后 6 个月时，收集视网膜图像和平均动脉压（MAP）。分析和总结视网膜血管，得出视网膜中央小动脉等效直径和视网膜中央小静脉等效直径。视网膜中央小动脉等效直径和视网膜中央小静脉等效直径均经过 MAP 校正。使用配对 t 检验比较连续时间点，显著性水平 P<0.01。从 13 周到 19 周的妊娠期间，MAP 下降（P=0.001），然后从 19 周到分娩时恢复到基线水平。这与血管口径在 13 周到 19 周的妊娠期间增加有关（视网膜中央小动脉等效直径：P<0.001，视网膜中央小静脉等效直径：P=0.007），并且从 19 周到分娩时恢复到基线水平。在未产妇和经产妇之间，视网膜中央小动脉等效直径或视网膜中央小静脉等效直径（未经校正和 MAP 校正）均无差异。微血管的扩张和收缩模式与整个妊娠期间的 MAP 变化相吻合，反映了外周阻力的变化。本研究深入了解了健康妊娠期间微血管的生理变化。这些结果可以作为基线，与妊娠病理条件下观察到的变化进行比较。
